Currently splitter refineries take into account parent when matching existing records. That is, they will only match records on label/idno/whatever with the parent_id specified in the mapping. If omitted the parent_id is assumed null which means only top-level records will match.
This is often the desired behavior, but for some datasets we need to disregard parent and just do a global match across the entire hierarchy.
An "ignoreParent" option should be added to all splitters working with hierarchical records.